I hovered my stretched 425 to 550 plastic frame Gaui today. The 550 blades have 4mm holes, but the grips are 3mm. I placed a brass bushing in the 4mm hole to make it 3mm, and then placed 3mm stainless bolts in the setup.

The blades were a bit loose by 450 standards, and on spool up there was a bit of twisting, but they smoothed out quickly.

After one pack the head bolts came out slightly warped or bent. I'm replacing these with plain steel 3mm bolts and will try tightening them more in case the start up "twist" was part of the issue.

With 550 blades should I drill out my plastic blade grips to 4mm, but then the bolts don't fit into the formed plastic insets.

You always want to use a shouldered bolt in the grips for maximum strength...Gaui has a 3mm bolt with 4 flanged "Hats" that are used for 4mm blade holes and makes them thicker...3mm I.D. x 3.97mm o.d. and 8mm wide flange x .5mm thick O.A. L. is 3.52...I'll find the P/N and send it to you...PT

I'm bummed I don't have a working helicopter this weekend. I left my starter for my nitro at a fun fly, broke 3 out of 4 canopy pegs on my mcpx, and I've given up on my tarot fbl on my 450 which randomly crashes every few flights.

Whoa Dude...That is serious!
If you have a cordless drill, make a starter shaft from an allen wrench and use bamboo skewers to make canopy posts...put the stock FB head back on the 450...You gotta make it happen!
Or you could just have a sim marathon...Gotta fly!

Another option is the 1/8" brass tubing I found at my LHS. 12" of it for $2.00. Slide a bamboo bbq stick inside it and cut it off with a hacksaw and it's worked fine. I also snugged down the grip bolts and need to snug them down more. No more bending.

Not sure how the Gaui plastic "hats" are supposed to do much, or even fit with the thicker blade root thickness that is a snug fit as it is.

I put the long boom on with cheap 550 fiberglass blades from helidirect, using some spacers PT gave me (big thanks!). Now I have to figure out what the heck is wrong with my ESC and/or motor. When I tried it with 425 blades it seemed week with a low headspeed, so I did two things: (1)switched to long blades, hoping that maybe my mystery motor (not the brand, but I have no idea what it is) might have been a low KV motor that would run the long blades. (2) I bought a program interface for my Castle ESC to make sure that is set up. I used pretty much the defaults with medium spool up. Well, it has just barely enough power to get up in a hover with such a slow head speed that the tail barely holds. After about 2 minutes, the motor is barely warm, the batteries cold, but the ESC is pretty darn warm. I have no experience with Castle ESC's and no experience with electric bigger than a 450, so I'm just starting to understand the KV-ESC-gearing-blades soup. Any advice, or do I need to just try a different ESC and/or motor to see what is up? On that note, for a motor, I was considering this one if I have to change it out--any experience or input?http://www.hobbyking.com/hobbyking/s...00_class_.html

...Well, Let's review your set up...
What motor was that...850 or 1100?
What is your gear train...Pinion,Front,OWB( all others pretty much set)
What is the throttle maxed at?
Pitch curve?
What tail blades?
I think all you need is to fine tune it now but the ESC timing may be an issue...
PT

I have a picture of the motor on another thread...I don't know what it is. It has a 13 tooth pinion (not 11 as I said in another post), 50 tooth front main gear, and 19 T one way gear. 61 tooth rear main gear. I was setting the throttle curve crazy high in normal just to get it off the ground. I switched it to idle up to make sure I was running 100% T curve. Throttle end point 100%, curve 100% in idle up and anything above mid-stick. Tail blades are 69mm from tip to center of the bolt hole (I think those are the larger size recommendation?). Pitch curve in idle up is linear from full negative to full positive. I didn't actually measure the pitch angle but I would guess +/-11 degrees, not too steep. You might be on to something if it is timing. Doesn't that have something to do with how many poles a motor has? I wish I could figure out what motor this is. Pic on this link.http://helifreak.com/showthread.php?t=445800

O.K.
We need to find out what that motor is but in the short term, do you have a 14T or 15T pinion? From what you are describing, the next test will be to increase the HS and see how it flys...I have a 14T I can send, but then my stock jumps to 20T...
You might order a 15T and 16T to try and keep in your parts box for the "Next" build...
PT

...14/50 is getting better....60 front main is going the opposite direction!
15/50/20/61 and 1100kv motor is sweet spot...14/42 is another but look out for hot gears and kinda fast for 550 blades...you won't know unless you try it. This is all based of course on a 1100kv motor